Abstract

The combination of a GaAs semiconductor saturable absorbing mirror (SESAM)¹ and a low-threshold laser geometry² has allowed the efficient production of stable low-noise femtosecond pulses. The highly asymmetric 4-mirror Cr³⁺LiSAF laser was pumped by 2 polarisation-combined narrow-stripe AlGaInP laser diodes each providing a maximum available power of 40mW incident on the crystal facet. The cw oscillation threshold of the laser was 16mW and the pulse repetition frequency was 153MHz. When output coupling through a high reflecting (HR) end mirror, the laser produced stable, sub 70 fs transform limited pulses at an average output power of 1mW. Modelocking could be sustained with pump powers as low as 21 mW.

© 1998 IEEE